This invention relates in general to media files delivery systems, and in particular to a system and method using multicast and unicast delivery of media files to consumers.
Live television programs may be delivered through a delivery medium such as coaxial cables, optical fibers or twisted pairs to subscribers, where the capacity is limited by the bandwidth of the delivery medium. With the introduction of high definition television programs, the increased number of channels that are offered to cable subscribers, and the development of the use of internet protocol (IP) to deliver television programs (IPTV), there is a need for increasing the efficiency in bandwidth use of the delivery medium in digital video transmission of television programs.
It is beneficial to use internet protocol (IP) multicast to deliver the television program for improved access network bandwidth efficiency. This is particularly true for live television programs for which a large number of viewers may be interested in receiving the program stream simultaneously. This may be done by delivering a video stream in multicast mode using the User Datagram Protocol (UDP) perhaps in conjunction with Real-Time Protocol (RTP). However, many client devices do not support this type of delivery and instead utilize Hypertext Transfer Protocol (“HTTP”) to retrieve a sequence of media file objects from a file server. The same problem is encountered whether the live media files are delivered by means of coaxial cables in cable television, by optical fibers in internet protocol television (IPTV) systems or by twisted pairs in digital subscriber line (DSL) networks.
It is therefore desirable to provide a system and method by which such problems are alleviated.